Switch

ABSTRACT

A switch device for switching an electrical connection between two connection parts is disclosed. Conventional switch devices comprise a contact lever having a switch contact, the flow of current taking place by way of the contact lever when the switch device is closed. To achieve a rapid switching process, a low mass inertia of the contact lever is required. However, this generally leads to a lower current capacity. By arranging the lever-side switch contact on a separate electrical connection device, it becomes possible to separate the function of current conduction from the function of contact guidance. Since the contact lever therefore no longer performs any current-conducting function, it may be optimized in mechanical respects exclusively.

FIELD OF THE INVENTION

The invention relates generally to switching devices, and, moreparticularly, to a switch device including a lever-side switch contact.

Referring to prior art FIG. 2, a switch device, such as for example afast direct-current switch, is diagrammatically shown. The switch devicecomprises a first and a second rigid connection part 5, 4 for connectinga circuit to be switched and a movable contact lever 1 mounted rotatablyabout an axis 6. On the contact lever 1, there is a contact plate 2 forproviding switch contact on the lever side. By actuating the contactlever 1, a contact can be made between the contact plate 2 and a switchcontact of the first connection part 5, whereby the circuit is closedacross the two connection parts 4 and 5 (cf. switch condition in FIG. 2,in dot-dash lines).

According to the prior art, the contact plate 2 is fixed to the movablecontact lever 1, which is electrically connected by way of a flex band 3for example to the second connection part 4. Instead of the flex band 3,current pins, friction contacts or the like are possible as connectingdevices between the contact lever and the second connection part 4. Thusthe circuit to be switched in the present example is closed as in FIG. 2across the two connection parts 4 and 5, the contact lever 1 and theflex band 3.

Points of contact transition in switch devices lead to increasedelectrical losses and interfere with heat flow. Particularly in thefield of opening switch contacts in safety circuit devices, optimalconformation is required. For current limitation, a fast opening of thecontact after occurrence of a short circuit is required. The contactlever should be of such conformation as to meet the following mechanicaland electrical requirements.

In mechanical regard, the contact lever should exhibit a minimal massinertia, in order to make possible a fast switching operation. Arequired high current capacity results in a maximal contact levercross-section and a minimal specific resistance of the contact levermaterial as electrical requirements.

From the aforementioned requirements, however, it is apparent that animprovement in mechanical properties generally leads to an impairment ofthe electrical properties, and vice versa.

SUMMARY OF THE INVENTION

In an exemplary embodiment of the invention lever-side switch contact isarranged on a connecting device to provide a switch, the function ofconducting current and heat is separated from the function of contactguidance. Thus the contact lever performs purely mechanical guidancefunctions, so that the requirements imposed on it as to current capacityare eliminated. Owing to the separation of the current conductivefunction from the contact guiding function, the contact lever may beproduced in light-weight construction with low mass inertia, fromelectrically non-conductive material for example.

The conformation of the switch device of the invention permits the useof a relatively long, flexible connecting device such as for example aflex band, whereby a conformation having a positive influence on servicelife can be realized.

Further, the reduction of contact transition points and the directconnection of the lever-side switch contact to the connection deviceachieve a high thermal and electrical conductivity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a representation in principle of the switch deviceaccording to the invention;

FIG. 2 shows a representation in principle of a switch device accordingto the prior art; and

FIG. 3 shows a perspective view of an example of an embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In an exemplary embodiment of the present invention, the contact plate 2is arranged directly on the flex band 3 serving as movable connectingdevice. In to the switch condition shown in dot-dash lines, the path ofcurrent with switch device closed passes solely by way of the twoconnection parts 4 and 5 and the flex band 3. The function of thecontact lever 1 is thus limited to contact guidance, and so it may bemade of non-conductive material. Besides, the current transition pointbetween the flex band 3 and the contact lever is eliminated.

The flex band is preferably of such shape conformation that as low-wear,low-closure a switch operation as possible is obtained. This may forexample be done by means of a suitable curvature and attachment to thesecond connection part 4.

FIG. 3 shows a schematic view of an example of embodiment of tie switchdevice according to the invention as a fast direct-current switch. Aflexible copper band 3 is so connected at its bottom end to the secondconnection part 4 that it is oriented towards the first connection part5. The copper band 3 exhibits a precurvature, so that mechanicalstresses arising in switch operation are reduced. Besides, the copperband comprises a slit 8 into which the contact lever 1 is partly fitted.At the top of the copper band 3, an electrically conductive contactplate 2 is soldered directly to the copper band 3 or a suitableconnection support. The upper portion of the copper band 3 is fittedinto a recess of the contact lever 1, and preferably pressure-welded toachieve a solid electrical connection. At the top of the contact lever1, a pre-contact 7 is arranged, protecting the main contact from burningin operational switching processes and thus lengthening the service lifeof the main contact.

In general, a switch device for switching an electrical connectionbetween two connection parts is disclosed.

Conventional switch devices comprise a contact lever having a switchcontact, the flow of current being passed over the contact lever whenthe switch device is closed. To achieve a rapid switch operation, a lowmass inertia of the contact lever is required. But this generally leadsto less current capacity, By arranging the lever-side switch contact ona separate electrical connection device, a separation of the function ofcurrent conduction from the function of contact guidance is possible.Since the contact lever therefore no longer performs anycurrent-conducting function, it can be optimized in mechanical respectsexclusively.

While preferred embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustration and not limitation.

What is claimed is:
 1. A switch device for switching an electricalconnection between a first and a second connection part, the switchdevice comprising: a movable contact lever for switching a lever-sideswitch contact and a switch contact of the first connection part; anelectrical connection device electrically connected to the secondconnection part, the electrical connecting device comprising anelectrically conductive flexible band, the band having a slit aperturethrough which a portion of the movable contact lever is fitted; andwherein the lever-side switch contact is arranged on the electricalconnection device.
 2. The switch device claim 1, wherein the contactlever is comprised of non-conductive material.
 3. The switch device ofclaim 1 wherein the lever-side switch contact comprises a contact platearranged on the band.
 4. The switch device of claim 1, wherein the bandis a copper band.
 5. The switch device of claim 4 wherein the lever-sideswitch contact is soldered to the band.
 6. The switch device of claim 5wherein the band is pressure-welded at the lever-side switch contact. 7.The switch device of claim 1 wherein the band has a predeterminedcurvature which limits mechanical stress on the band.
 8. The switchdevice of claim 1, wherein an end of the copper band which ispressure-welded at the lever-side switch contact is fitted into a recessof the contact lever.
 9. The switch device of claim 1 further comprisinga pre-contact on the contact lever for contacting the switch contact onthe first connection part prior to the lever-side switch contact makingcontact with the switch contact on the first connection part.
 10. Aswitch device for switching an electrical connection between a first anda second connection part, the first and second connection partsseparated by a distance, the switch device comprising: a non-conductivemovable contact lever for switching a lever-side switch contact and aswitch contact of the first connection part, the contact leversubstantially spanning the distance between the first and secondconnection parts; an electrical connection device electrically connectedto the second connection part; and wherein the lever-side switch contactis arranged on the electrical connection device.
 11. The switch deviceof claim 10 wherein the electrical connection device comprises a flexband.
 12. The switch device of claim 11 wherein the lever-side switchcontact is soldered to the flex band.
 13. The switch device of claim 11,wherein the moveable contact lever is partly fitted into a slit apertureof the flex band.
 14. The switch device of claim 11 wherein the flexband has a predetermined curvature.
 15. The switch device of claim 10further comprising a pre-contact on the contact lever for contacting theswitch contact on the first connection part prior to the lever-sideswitch contact making contact with the switch contact on the firstconnection part.
 16. The switch device of claim 10 wherein the contactlever has a pivot point adjacent the second connection part.